1. Field of the Invention
This invention relates to magnetic card readers, and more particularly to a magnetic card reader which identifies a magnetic card, and insert it into the magnetic card reader.
2. Related Art
FIG. 3 is an explanatory diagram showing the arrangement of a conventional magnetic card reader. In the magnetic card reader, the magnetic card inserted into the reader is conveyed to a predetermined position to perform data recording and reading operations. In this case, in order to avoid the insertion of an incorrect card--different in kind, the magnetism of the card is detected with a prehead 101 provided at the card inserting inlet, and with a shutter operated in association with the prehead 101 the insertion of the incorrect card is prevented.
As for such a card reader, especially as for a small card reader, there is a strong demand for elimination of the prehead 101 to increase the space thereby to decrease the manufacturing cost. In order to meet this requirement, in one example of the magnetic card reader, a magnetic head 103 for magnetic data is also used as the prehead 101.
On the other hand, the magnetic card reader which is so designed that the magnetic head 103 operates also as the prehead 101, suffers from the following problem: For instance in the case where a card different in configuration or having a hole has been inserted in the card reader, the sensor operates erroneously, so that the card may be caught in the reader or cannot be taken out. This problem may be solved if, before the card has been fully inserted in the reader, it is detected whether or not it is a correct one.